Re: LOR in uipc_usrreq.c and kern_descrip.c

On Mon, 19 Sep 2005, Gleb Kozyrev wrote:

> Hello, All!
>
> While playing with wine-20050830 I saw the following:

Could you file a PR on this, and forward me the PR number?  This needs to 
be fixed, but will be a moderate amount of work that will likely have to 
happen after 6.0-RELEASE.  In theory there is a deadlock risk here, but my 
hope is that the chances are low that it will occur in practice.

Thanks,

Robert N M Watson

>
> =========Beginning of the citation==============
> lock order reversal
> 1st 0xc0971c60 unp (unp) _at_ /usr/src/sys/kern/uipc_usrreq.c:249
> 2nd 0xc0922160 filelist lock (filelist lock) _at_ /usr/src/sys/kern/kern_descrip.c:2127
> KDB: stack backtrace:
> kdb_backtrace(0,ffffffff,c0934d08,c09346f0,c08c04cc) at kdb_backtrace+0x29
> witness_checkorder(c0922160,9,c08571f2,84f) at witness_checkorder+0x564
> _sx_xlock(c0922160,c08571f2,84f) at _sx_xlock+0x50
> fdrop_locked(c1b41c60,0,c12f8f40,0,c08571f2) at fdrop_locked+0xa1
> fdrop(c1b41c60,0,3,c15d8d80,cc8e69d4) at fdrop+0x24
> closef(c1b41c60,0,c1703418,cc8e6a4c,c06762fc) at closef+0x35f
> unp_discard(c1b41c60) at unp_discard+0x43
> unp_scan(c1703400,c0676384) at unp_scan+0x80
> unp_dispose(c1703400) at unp_dispose+0x15
> sorflush(c20ac000,c20dac18,c20ac000,cc8e6b18,c067387e) at sorflush+0x119
> unp_detach(c233c604,cc8e6b30,c066bb84,c20ac000,c20dac18) at unp_detach+0xc5
> uipc_detach(c20ac000) at uipc_detach+0x4a
> soclose(c20ac000,c20dac18,0,cc8e6b5c,c0617fb8) at soclose+0x1e0
> soo_close(c20dac18,c15d8d80) at soo_close+0x4b
> fdrop_locked(c20dac18,c15d8d80,c12f8ed4,0,c08571f2) at fdrop_locked+0x88
> fdrop(c20dac18,c15d8d80,cc8e6ba8,c0654740,c08571f2) at fdrop+0x24
> closef(c20dac18,c15d8d80) at closef+0x35f
> fdfree(c15d8d80,c15fdb88,282754e4,c15d8d80,c0905500) at fdfree+0x473
> exit1(c15d8d80,100,cc8e6d30,c07f22fb,c15d8d80) at exit1+0x3f6
> exit1(c15d8d80,cc8e6d04,1,12b,292) at exit1
> syscall(3b,3b,3b,8089200,bfbfe67c) at syscall+0x22f
> Xint0x80_syscall() at Xint0x80_syscall+0x1f
> --- syscall (1, FreeBSD ELF32, sys_exit), eip = 0x281f3433, esp = 0xbfbfe2f0, ebp = 0xbfbfe30c ---
> =========The end of the citation================
>
> FreeBSD 6.0-BETA4 #0: Wed Sep 14, GENERIC kernel.
>
> -- 
> With best regards, Gleb Kozyrev.
>
>
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